珠江口盆地陆丰北新区现今地温场特征及生排烃OA

To clarify the thermal evolution and hydrocarbon generation potential of source rocks in Lufeng North half-graben(LFN),the available abundant data from Lufeng South half-graben(LFS)and the measured data of formation temperatures and vitrinite reflectance from drillings through source rocks were used to analyze the cor-relation between formation temperatures and burial depth by forward simulation.In addition,by extrapolation from the more-drilling area of LFS to the less-drilling area of LFN,the regional geothermal field of LFN was sys-tematically established for the first time.Based on this geothermal field model,the basin simulation genetic meth-od was applied to evaluate the impact of the geothermal field on the thermal evolution of source rocks,and further assessed quantitatively the hydrocarbon generation potential.Results show that firstly,LFN has lower geothermal gradient and higher temperature in the central areas of subsags,while higher geothermal gradient and lower tem-perature in the slope of subsags.The main source rocks of the Eocene Wenchang Formation in LFN have been mature in over-all at present,especially in the central aeras of subsags entering high-mature stage.Secondly,the biomarker fingerprints of drilled mudstones indicate for the first time that the upper Wenchang Formation con-tains source rocks of shallow lake and semi-deep lake facies,confirming that LFN has a good hydrocarbon poten-tial.Thirdly,LFN experienced two episodic oil expulsion(35.5-26.5 and 17.5-8.5 Ma)and the gas expulsion episode is 15-0 Ma.The order of hydrocarbon resource enrichment is:Subsag LF07＞Subsag HZ11＞Subsag HZ05,and the structural zones surrounding Subsag LF07 was identified as favorable exploration zones.